I've found quite a bit of information in the past few months reading advice on here as a guest. It's past time to make an account; I need some help with my daughter's 2001 Bonneville SSEi.

When she got it the rear shocks were blown and the Service Engine Soon light was on. She was told (first by the previous owner, then later by a mechanic) that that the light was from the suspension air compressor pump not working. A few days ago I replaced the rear air shocks with new air shocks (maybe I should have opted for a conversion to conventional shocks). I picked up a used suspension compressor - it has a 30 day warranty. I was also replacing the power steering pump at the same time so I couldn't start the car when I was putting the air shocks in. I used a regular air compressor to raise the shocks until they were close but I also had a bottle jack under the shock and jacked it up the rest of the way.

Now: the rear end is high and won't come down. I've barely heard the compressor run. I expected to hear it soon as I turned the car on, or just turned the ignition to "on", but about the only time I've heard it is when I've disconnected the arm from the position sensor and raised it up all the way.
Pulling the sensor arm down did nothing.
Neither did pushing the accessory air switch in the trunk.
Also, removing that switch didn't change anything.
Removing the ELC relay and/or fuse did not allow the rear to drop.
There are two fuses and two relays, one each for the air pump and the ELC. I've switched, one at a time, each of the four with an equivalent fuse or relay in the fuse box to make sure they were each working.
I'm not sure how the position sensor is supposed to "feel", it doesn't seem obviously bad to me but I don't know what "normal" is.

I know that the system is composed of the compressor, the position sensor, the rear integration module (RIM) and the accessory switch. I have heard the compressor kick on...but not much. I'm not sure where to go. Is it likely that the compressor is almost shot and I need to start with the compressor? Especially since it doesn't run a few seconds after the car is on? Or do I need to look for a RIM...or position sensor? Help!!!

A little more background: my daughter is graduating from college a month from now and is moving from here in Nebraska to Wisconsin in two months. She bought her 2001 Bonneville SSEi from her friend's brother-in-law about two years ago. He had kept things going but he was more of a jury-rigger. I know, sometimes that works, but as a quick example: the spare donut was ruined so he tossed a regular tire he had immediate access to in the trunk as a spare. The only qualification for it being a viable spare? He could make the bolt holes line up. So the "spare" was a 215/65 R15 with 10 bolt holes in it, 5 would line up but the other 5 wouldn't. (The car takes 235/55 R17 tires.)

I've been working on it off and on but just for the past few months to get some long overdue things taken care of. She's embarrassed taking it to a mechanic, hearing them list the things wrong with it and ignoring most of it because it's too expensive for her to have them fix. At this point I'm rather wishing that she had just written it off and planned to sell it and found a different vehicle. But now...hopefully she can drive it long term; it has just over 150,000 miles.

It started when the mass air flow sensor went out. She freaked at the $600+ bill and the laundry list of issues. She's also had a mechanic put on three new rotors, some new tires and a fuel filter. Since then I've replaced the belts, intake manifold gasket, thermostat, upper radiator hose, plugs and wires, a few light bulbs, the compartment air filter, changed the supercharger oil and the transmission fluid, flushed the brakes, replaced the radiator, power steering pump and intermediate shaft with used ones, rebuilt the rack and pinion with new seals and put on new tie rod ends. And I got her a regular 235/55 R17 as a spare. The shocks wasn't the first project I attempted on this car.

So - compressor, position sensor, RIM...where do I go from here?

Thanks,
Brian